Gasless, Mechanized, Field-Welding Of Tubular Structure

ABSTRACT

A system and method provide gasless, mechanized, field welding of an exterior of a tubular structure such as a pipeline, without the need for an enclosure. An embodiment consolidates some of the welding equipment on a skid for ease of transport to and from a remote worksite. The gasless weld may be achieved despite the presence of wind, by precisely controlling an arc voltage as disclosed. The footprint and weight of the system may be minimized, along with the associated labor, expense, and environmental impact otherwise incurred by conventional welding techniques using enclosures.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a non-provisional of U.S. Patent ApplicationNo. 63/080,413, filed on Sep. 18, 2020, the entire disclosure of whichis incorporated herein by reference.

BACKGROUND

Welding is a common technique in manufacturing for joining any number ofcomponents of similar composition to form a structure of virtually anydesired size. Welding is commonly used to join many types of metals, aswell as certain plastics. Most types of welding involve melting aportion of the pieces to be joined near an interface between thosepieces. The melted material runs together and re-hardens as it cools, sothat the two pieces become an essentially unitary structure. Thisprovides an advantage over other joining processes like soldering andwelding, in which a filler metal is instead melted at the interface,leaving two distinct parts joined by the solidified filler material.Other types of welding known in the art generally as “solid-state”welding do not melt the parent material. However, these are generallynot suitable for larger structures.

Pipelines are among the many large structures that can be formed bywelding. Pipelines are long vessels constructed to carry fluids, such aspetroleum, chemicals, water, or sewage over long distances, from thesource to some downstream destination where the fluids may be processedand/or sold. Multiple pipeline segments may be consecutively arrangedend-to-end and joined to create a pipeline extending hundreds orthousands of miles or kilometers long. The enormity of such a structure,however, presents numerous challenges in its fabrication. The resultingeconomic and environmental impact can be significant.

Currently, many pipelines are constructed using gas-shielded weldingtechniques to achieve the desired weld quality needed to safely conveyfluids and minimize the risk of failure or leakage. Gas-shieldedtechniques involve supplying an inert gas to the joint to displaceoxygen and other contaminants that would otherwise degrade the qualityof the weld joint. The use of gas-shielded welding on pipelines, inturn, requires the use of large enclosures (alternately referred to asshacks, huts, or houses) around every pipeline joint to be welded, suchas shown in FIG. 1. These large enclosures are necessary, in part, toshield the pipeline joint to be welded from wind common to large, openspaces. Such wind and other external factors would otherwise blow awaythe inert gas supplied to the joint. Various welding equipment is alsomounted to these large enclosures, adding to their size, weight, andcost. The shacks, in turn, require significant expenditures of humanresources, equipment and capital especially if their location need to bein tight environmental terrains. One such terrain would be a trench asshown in FIG. 2. As can be seen, the trench requires an enormous amountof excavation to accommodate these shacks.

Transportation and implementation of these large enclosures introducesits own set of costs and challenges. For example, special vehicleshaving metal, tank-like treads or tracks are needed to transport them.The metal tracks can damage road surfaces, and the regulatoryrequirements in place to mitigate this damage adds to the cost andcomplexity. On-site, the use of these large enclosures also requiresexcavation of large portions of earth, with resulting environmental andeconomic impact.

The industry is always looking for new and better ways to reduce costsand minimize environmental impact. The present disclosure, havingidentified the foregoing needs, will now address these risks withvarious systems, devices, and methods that may represent a step-changeimprovement in how pipelines and other large, tubular structures may beconstructed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevation view of a pipeline under construction requiringthe use of large enclosures known as shacks.

FIG. 2 is an elevation view of the pipeline as lowered into a trench asit is being built, as an example of the very large size of trenchrequired for receiving such a shack.

FIG. 3 is a schematic, plan view of a welding system for welding atubular workpiece according to an embodiment of this disclosure.

FIG. 4 is a side view of an example implementation of the welding systemof FIG. 3.

FIG. 5 is a perspective view of the tubular workpiece on which the guidetrack and mechanized carrier are installed

FIG. 6 is a side view of an example implementation of the helper stationwith various equipment installed on or connected thereto.

FIG. 7 is a side view of the wire feeder carried on the helper station.

FIG. 8 is a perspective view of the gasless torch connection at whichvoltage is locally measured.

FIG. 9 is a cutaway view of an example coaxial cable for facilitatinglow-impedance, high-accuracy control of the voltage at the gasless torchconnection.

DETAILED DESCRIPTION

A system and method are disclosed for gasless, mechanized, field weldingof an exterior of workpiece. In some examples, the workpiece may be atubular structure such as a pipeline. Gasless welding may be performedin the field without an enclosure, even in the presence of wind. Thefootprint and weight of the system may be minimized, along with theassociated labor, expense, and environmental impact otherwise incurredby conventional welding techniques using enclosures.

In an example embodiment, the enclosure is eliminated via the use ofgasless welding techniques, which do not require an auxiliary inert gassupply during welding. The gasless welding may be achieved in the fieldwith a system configuration that combines, for example, precise localvoltage measurement of the arc at a workpiece to be welded,low-inductance power and signal transmission using a coaxial cablecoupling the gasless torch to a welding machine, and preciselycontrolled height of the torch from the workpiece using a mechanizedcarrier that travels along the workpiece on a guide track. In someexamples, the guide track is generally circular to conform with atubular workpiece, although other guide tracks may be configured to movealong straight sections or non-circular sections. By eliminating theneed for an enclosure, particularly when welding a pipeline in thefield, and by optionally consolidating various welding equipment on askid that can be relocated on a transport vehicle without disassembly,the size, weight, and footprint occupied by the welding equipment may begreatly reduced as compared with conventional pipeline welding.

This disclosure is also directed, in part, to a portable helper stationfor welding a workpiece in the field. The portable helper station may bea subset of a larger system disclosed herein, which may be fieldassembled with any of a variety of other equipment. The helper stationmay be used in conjunction with a gasless welding system and method suchas described herein. Alternatively, the helper station may be configuredfor use with a gas shielded system and method.

In an example embodiment, the helper station comprises a framepositionable to orient the helper station with respect to the workpieceto be welded. The frame is transportable to a welding site and removablysecurable to a lifting arm, which may be a mechanized lifting arm (e.g.electrically and/or hydraulically raised, lowered, and/or rotated). Awire feeder may be carried on the frame, for feeding a consumablewelding wire to a gasless torch in electrical communication with awelding machine that is interconnected with the helper station in thefield. The wire feeder and gasless torch may generate an electrical arcbetween the consumable welding wire and the workpiece. A user interfacemay be electrically connected and physically mountable on the frame. Theuser interface may have at least a first controller configured tooperate the wire feeder, and one or more other controllers such as tocontrol the motion of the lifting arm, the motion of mechanized carrieron a track, and/or the position of the gasless torch with respect to themechanized carrier.

For purposes of this disclosure, there are four main categories ofwelding identified. These are generally categorized according to thelevel of human intervention required. A first category is manualwelding, which involves a hand-held electrode or “stick” above theworkpiece. The stick gets consumed while welding, and the user maymanually adjust a spacing between the stick and the workpiece. A secondcategory is semi-automated welding using a hand-held torch. A continuouselectrode may be fed to the torch, and an inert gas may be supplied fromthe torch to protect the weld. A third category is mechanized welding,wherein the torch, itself is guided by a device, and a human providesactive, electronic control input to make minor adjustments to the devicewhile welding. An inert gas may also be supplied to protect the weld. Anexample of a mechanized welding system is the Bug and Band™ family ofwelding systems provided by Pipeline Supply & Service, LLC. In a Bug andBand system, a band disposable about a circular workpiece in thevicinity of a joint to be welded provides a track to guide a weldingdevice (the “bug”) that moves along the track in response to humaninput. A fourth category is automated welding, in which a robot performsthe entire weld from start to finish, generally without active humaninput during the welding.

As used in any of the following embodiments, the “torch” may refer to awelding gun, that can be alternately referred to as a torch, gun, orwelding torch. The torch may be the mechanism that is nearest the workpiece being welded where the welding wire exits.

FIG. 3 is a schematic, plan view of a welding system 10 for welding atubular workpiece 20 according to an embodiment of this disclosure. Thetubular workpiece 20 may be at a worksite 5. The worksite 5 may beexposed to an abundance of wind 15 as would typically be present inlarge, open places where pipelines are constructed. And yet, the system10, according to the gasless welding and other various aspects below,may weld without the need for a weld shack such as in FIG. 1.

The tubular workpiece 20 may be any generally tubular structure formedof a base material that can be welded. The tubular workpiece 20 may bereferred to in specific examples as a pipeline 20 or pipeline segment byway of example and not by limitation. The tubular workpiece 20 may be aferrous or non-ferrous metal although aspects of this disclosure may beapplied to any tubular structure of weldable material. The tubularworkpiece 20 is also of generally circular cross-section in thisexample, although a tubular workpiece need not have a circular orperfectly-round cross-section, and so other shapes are also within thescope of this disclosure in terms of what may be welded. The weld may beperformed, for example, along an interface between two pipeline segmentsbutted end-to-end. Alternatively, the weld may be performed along aportion of the tubular workpiece 20 to be repaired, such as a crack.

The system 10 in this example includes a plurality of welding equipmenttransportable to a work site 5, optionally on a skid 12 and withoutdisassembly prior to transport. Thus, substantially all of the equipmentmounted on the skid may remain assembled/secured to the skid duringtransport if desired. The welding equipment on the skid 12 in FIG. 3includes, for example, at least one welding machine 30 (two redundantunits are shown here) for generating a controlled voltage, a powersupply 40 for powering the welding machine 30, and a boom 50 including alifting arm 52. Additional welding equipment may be provided at a helperstation 60. The power supply 40 may generate or otherwise supplyelectrical power to be used by the welding machines 30 and otherequipment discussed herein. A main power input schematically shown at 42provides the power of whatever kind consumed by the power supply 40itself. For instance, the main power input 42 may be a main electricalpower source provided for this skid 12 and for various other systems onthe worksite 5, however that may be supplied, such as by on-sitegenerators, a connection to local power grid, and so forth. The powersupply 40 may generate a specific range or set of one or more electricalcurrent parameters suitable for at least the welding machines 30.Optionally, the welding machines 30 and/or the power supply 40 could beconfigured to also generate a specific range or set of one or moreelectrical current parameters suitable for use by the various otherequipment in the system 10, such as specific voltage and currentparameters of direct current (DC) and/or alternating current (AC) usedby different equipment.

The system 10 may also support wireless data gathering and transmissionfrom the skid or helper to a remote location (cloud, onsite data center,customer data center, data center, etc.) Electrical and data lines maybe provided as needed between any of the various welding equipment,using any of a variety of cables, connectors, buses, wires, wiringharnesses, wireless connections of various protocols, and so forth. Someof these connections are indicated by way of example with dashed linesin FIG. 3. Electrical power and data or communication cables 54 are alsoshown routed along the boom 50 from components of the system 10 on theskid 12 to components of the system 12 at the helper station 60. Itshould be understood that physical and/or wireless connections can bemade as needed, directly or indirectly, between different components ofthe system 10, and not every possible combination of electrical powerand signal data communication is indicated in the drawing.

The welding machines 30, power supply 40, boom 50, and/or other weldingequipment (although not necessarily all the welding equipment) areoptionally mounted in this embodiment on a skid 12, for transportabilityof at least a portion of the welding system 10 to and from a work sitewhere the pipeline or other tubular workpiece 20 is to be welded. Theskid 12 may be any portable structure to which some of the weldingequipment may be mounted to transport that welding equipment on the skidto and from a worksite 5. The skid 12 in this example is an openstructure for easy user access to the welding equipment mounted thereon.It may have a strong frame for the welding machine(s) 30, power supply40, boom 50, and other welding equipment to be mounted to. The skid 12and various equipment on it may be assembled and/or stored when not atthe work site, such as at a remote storage or service facility (notshown).

The skid 12 and welding equipment mounted thereon may then be readilyloaded onto and unloaded from a transport vehicle 14, depicted as aflatbed truck in this example. Conventional lifting equipment may beused to load or unload the skid 12 from the transport vehicle 14, suchas using the tines of a forklift 16. Depending on the particularworksite and the job to be performed there, the skid 12 may eitherremain on the transport vehicle 14 while the welding job is completed,or unloaded from the transport vehicle 14 at the worksite. Because thesystem 10 is capable of welding a pipeline or other tubular structureoutdoors without an enclosure to protect from the wind 15, the weight ofa conventional welding shack can be eliminated. The weight of the skid12 and the equipment mounted on the skid 12 may be very light weight incomparison. In at least some embodiments, the weight of the skid 12 andthe welding equipment mounted thereon is less than about 7500 pounds(3400 Kg) in some embodiments, or up to 8500 pounds (3900 Kg) whenincluding an expandable cover. As a result, the skid 12 may be easilytransported to and from the worksite 5 without the heavy metal treadsand special transportation measures and precautions normally associatedwith pipeline construction. Whereas conventional methods may require theuse of metal treads to support the weight of a shack, the transportvehicle 14 in the present system may use non-metal (e.g. rubber) treadsdriven by one or more wheels, or even conventional tires such as in theexample of a truck. This makes it easy to load the welding equipmentonto a wide variety of transport vehicles with a much lower risk ofdamage to the roadways. However, although helpful, the skid andtransport vehicle are not strictly required in every configuration. Ifdesired, components of the system 10 could be individually transportedand then assembled at the worksite 5.

Referring still to FIG. 3, the helper station 60 is secured to andsuspended from the lifting arm 52 of the boom 50. The helper station 60may comprise a frame 61 for supporting various equipment. The helperstation 60 is configured, in part, for the convenience of a human userwho may monitor and/or participate in the mechanized welding of thetubular workpiece 20. The helper station 60 is positionable at theworksite to orient the helper station 60 with respect to the tubularworkpiece 20 to be welded and the human user who may operate it. Forexample, the skid 12 itself may be positioned and oriented at theworksite to position the helper station 60 near the tubular workpiece 20to be welded. Further, the boom 50 may be moveable with respect to theskid 12, such as by raising or lowering the lifting arm 52 about an axis53, or azimuthally by rotation of the lifting arm 52 about a pivot asindicated at 55. Thus, placement of the skid 12 and/or positioning ofthe lifting arm 52 may be used to bring the helper station 60 intoproximity of the tubular workpiece 20 so that various other equipment iseasily accessible by the user.

The helper station 60 is physically accessible to a human user who mayperform or help with various aspects of welding the pipeline 20 usingvarious input devices and with the help of the mechanized equipmentdisclosed. For example, the human user may be a skilled welder, who maybe stationed at the helper station 60 within visual distance from thetubular workpiece 20 to visually monitor and adjust the weld process ifneeded. The helper station 60 carries one or more automatic wire feeder70 for feeding a consumable welding wire 72 to a gasless torch 62 inelectrical communication with the welding machine 30. The gasless torch62 receives the consumable welding wire 72 as it is fed from the wirefeeder 70. The gasless torch 62 receives a controlled voltage from thewelding machine(s) 30 to generate an electrical arc between theconsumable welding wire 72 and the tubular workpiece 20. Any number ofuser interfaces are electrically connected and optionally physicallymountable on the helper station 60, such as a first controller 76 and asecond controller 78 further discussed below. The first controller 76may be used to operate the wire feeder 70, and the second controller 78may provide for remote control of the welding process, for example. Oneof these or another controller may be used to control the boom.

The system 10 includes mechanized equipment in this example, to helpcontrol aspects of the welding process that may be harder for a humanuser to adjust. In particular, the system 10 includes a guide track 22that is positionable about the tubular workpiece 20. The tubularworkpiece 20 in this example has a circular cross-section and the guidetrack 22 may be shaped to conform to the cross-sectional shape. In thiscase the cross-sectional shape is circular, but a guide track mayalternately be configured for other cross-sectional shapes (e.g. squareor hexagonal tubing). A mechanized carrier 24 is moveably secured to theguide track 22 and moveable along the guide track 22, to guide thegasless torch 62 at a precise, controlled distance from the tubularworkpiece 20. Any of a variety of tracks may be configured according tothis disclosure whereby a mechanized carrier is moveably secured to thetrack. Just one example of a suitable track and mechanized carrier isthe Bug and Band™ system offered by Pipeline Supply & Service, LLC,wherein the “band” comprises the track and the “bug” comprises themechanized carrier. Instead of the human operator manually holding thegasless torch 62 by hand, the gasless torch 62 is clamped to themechanized carrier 24, and the mechanized carrier 24 moves along theguide track 22 while holding the gasless torch 62 adjacent to thetubular workpiece 20 to weld along a weld path 26. This contributes, inpart, to performing a quality weld, such as by holding the gasless torch62 at a consistent distance from the tubular workpiece 20 and creating auniform, quality weld bead.

A user interface is provided in electrical communication with themechanized carrier 24, for controlling one or both of motion of themechanized carrier 24 along the guide track 22 and a lateral position ofthe gasless torch 62 relative to the weld path 26, in response toreal-time user input during welding of the tubular workpiece 20. Theuser interface in this example comprises a first controller 76 having agraphical user interface (GUI) for controlling the wire feeder 70 and asecond controller 78 for controlling movement of the mechanized carrier24 along the guide track 22. Any of a variety of inputs may be providedon these handheld controllers 76, 78, such as physical or electronicbuttons, dials, switches, and the like, or an interactive touchscreen.For example, the second controller 78 may be used to selectively startand stop the welding process and coordinated movement of the mechanizedcarrier 24 along the guide track 22. The second controller 78 may alsobe used to control a relative position of the gasless torch 62, such asthe lateral position, for the human operator to follow the intended wellpath 26.

Although the system 10 of FIG. 1 is configured for assistance by a humanoperator, alternative embodiments may instead use an automaticcontroller in electrical communication with the mechanized carrier 24.For example, the automatic controller may comprise an optical sensor forsensing a position of the mechanized carrier 24 relative to the tubularworkpiece 20 and the weld path 26. The optical controller may controlmotion of the mechanized carrier 24 along the guide track 22 in responseto the sensed position, such as to start/stop and steer left/right toclosely track the desired weld path 26. Then, instead of hand-heldcontrollers 76, 78, the automatic controller may be wired into orotherwise included with control logic, which may be provided on or inconnection to the helper station 60.

In addition to eliminating the need for a bulky, heavy shack or otherweld enclosure, the arrangement and configuration of the weldingequipment on the skid 12 results in a desirably very compact system witha relatively small footprint. In a further aspect, the power supply 40has a cabinet with one-sided access. Everything the human user may needto access is available on the same side 44 of its chassis. For instance,the electrical outlets and maintenance panel may be both accessible fromthe same side 44. This may avoid the need for standing room on theopposite side 46 of the chassis 44 indicated with an “X.”

Additional figures are provided to show particular exampleconfigurations of the system 10 of FIG. 3 and examples of variouswelding equipment included therewith. One of ordinary skill in the artwill appreciate that the system 10 and related methods disclosed and/orclaimed may be assembled in some configurations using items of equipmentthat, individually, may be commercially available. Embodiments of thisdisclosure are not, however, limited to the specific items of equipmentshown.

FIG. 4 is a side view of an example implementation of the welding systemof FIG. 3 as implemented for demonstration purposes in a lab-typesetting. The tubular workpiece 20 in this example is a pipeline segmentpropped up on a stand 28. The arm 52 of the boom 50 is moveable in thisexample, to raise and lower the arm 52 and the helper station 60suspended therefrom. Electrical power and data communication cables 54are routed along the arm 52 from the welding equipment on the skid 12 tothe helper station 60. A cabinet is provided for receiving the weldingmachines 30 and power supply 40, with room for additional equipment.Alternatively, the skid 12 could be shortened to further reduce thefootprint of the skid 12 where additional equipment capacity is notrequired. A user may stand and work in a work area 18 with convenientaccess to the tubular workpiece 20, the welding machines 30, the powersupply 40, and the helper station 60, while remaining within the workarea 18.

FIG. 4 further illustrates an optional collapsible cover 90 that can beused at a remote worksite to help protect the user and equipment. Thecollapsible cover 90 may be coupled to the boom 50 over the helperstation 60. The collapsible cover 90 can be opened to an expandedposition 92 that covers an area overhead of one or more of the helperstation 60, the mechanized carrier 24 (FIG. 5), and a portion of thetubular workpiece 20 including the weld path. The collapsible cover 90may be moved to a collapsed position as indicated at 94 (dashed linetypeshows it being moved between fully open and fully closed), fortransporting the system 10 to and from the worksite 5.

FIG. 5 is a perspective view of the tubular workpiece 20 on which theguide track 22 and mechanized carrier 24 are installed. As can be seen,the guide track 22 in this example is generally circular to conform tothe generally circular outer diameter (OD) of the tubular workpiece. Thesystem 10 works with a tubular workpiece 20 having a diameter as smallas about 8 inches (20 cm). For example, in cross-country pipelinewelding 50 miles can be run at 36 inch diameter.

An attachment mechanism is provided on the mechanized carrier 24 forattaching the gasless torch 62 at the desired position. An alternativeconfiguration optionally allows for interchangeably supporting thegasless torch 62 or one or more other tools, such as a paint sprayer ora sand blaster. Thus, in addition to being able to weld the tubularworkpiece 20 using the gasless torch 62, one of the other attachmentsmay be used to paint or sand-blast at least a portion of the OD of thetubular workpiece 20, such as along the weld path 26 of FIG. 3.

The gasless torch (FIG. 3) may be held on the right or left side of themechanized carrier 24. The gasless torch could be located at anyorientation to the mechanized carrier that allows access to the tubularworkpiece 20 and weld path 26. The guide track 22 is offset a uniformdistance “h” from the OD of the tubular workpiece 20, to maintain thegasless torch a uniform distance from the OD as the mechanized carrier24 travels around the tubular workpiece 12. In one or more embodiments,the guide track 22 may have a certain amount of flexibility orconformability, or may otherwise be pre-fabricated, to adapt toworkpiece cross-sections that may be slightly off-round or evendifferent shapes.

FIG. 6 is a side view of an example implementation of the helper station60 with various equipment installed on or connected thereto. The helperstation 60 is configured for use with a gasless welding system andmethod as described herein, but, alternatively, may support variouswelding equipment installed on or connected thereto in association witha gas-shielded welding system or method. The frame 61 of the helperstation 60 is open in this example, with space between the frame membersto allow for ingress and egress of various cabling and other features. Arobust, flexible guide cable 64 is provided for guiding the consumablewelding wire 72 as it is being fed from the automatic wire feeder 70.The guide cable 64 contains a housing lined with a polymer for receivingthe consumable welding wire along at least a portion of a guide pathfrom the wire feeder 70 to the gasless torch 62. A sectional view of theflexible guide cable 64 shows an internal example configurationincluding an outermost protective housing, an inner housing 74 withinthe protective housing, and a polymer liner such as apolytetrafluoroethylene liner 76 inside the inner housing 74. Theconsumable welding wire 71 is disposed within thepolytetrafluoroethylene liner 76, which facilitates uniform feeding ofthe consumable welding wire 71 to the gasless torch. The uniform feedingof the consumable welding wire 71 helps ensure a uniform and stable wirefeed rate (length of wire per unit of time) is delivered to theworkpiece. Since gasless welding is particularly sensitive to wire feedspeed and voltage at the workpiece, this polytetrafluoroethylene-linedcable configuration is yet another aspect that helps enable gaslesswelding approach that eliminates the shack.

FIG. 7 is a side view of the automatic wire feeder 70 carried on thehelper station 60. A panel is open to reveal the consumable welding wire71 coiled around a spool 73. The wire 71 is fed from the spool 73 to thegasless torch via an injector 77.

FIG. 8 is an exposed view of a connection 66 of the gasless torch 62 atwhich voltage is locally measured at the workpiece instead of or inaddition to at the welding machines. A voltage sensor included on thegasless torch 62 senses an arc voltage at the tubular workpiece. Due toimpedance losses in electronic cabling, the voltage measured at thegasless torch 62 is more representative of the actual voltage of the arcthan a voltage taken at the welding machine. This helps ensure tighterand more responsive control of the voltage to further facilitate agasless welding approach. The welding machine 30 of FIGS. 3 and 4 isconfigured for adjusting the controlled voltage supplied by the weldingmachine 30 to the torch 62 in response to the arc voltage sensed by thevoltage sensor. A difference between the controlled voltage supplied bythe welding machine 30 (FIG. 3) and the arc voltage sensed by thevoltage sensor in the gasless torch 62 in some embodiments is less than+/−1 V.

FIG. 9 is a cutaway view of an example coaxial cable 80 for facilitatinglow-impedance, high-accuracy control of the voltage at the gasless torchconnection. The coaxial cable comprises an inner wire 82 disposed withinan outer wire 84 and separated by an insulating layer 85. The coaxialcable supplies the controlled voltage from the welding machine 30 to thegasless torch 62 of FIG. 8.

1. A system for welding a tubular workpiece, the system comprising: aplurality of welding equipment for transportation to a work site, thewelding equipment including a welding machine for generating acontrolled voltage, a power supply for powering the welding machine, anda boom including a lifting arm; a helper station secured to the liftingarm, positionable to orient the helper station with respect to thetubular workpiece to be welded; a wire feeder carried on the helperstation, the wire feeder configured for feeding a consumable weldingwire; a gasless torch in electrical communication with the weldingmachine and configured for receiving the consumable welding wire fromthe wire feeder and generating an electrical arc between the consumablewelding wire and the tubular workpiece; a guide track positionable aboutthe tubular workpiece; and a mechanized carrier moveably secured to theguide track and moveable along the guide track while holding the gaslesstorch adjacent to the tubular workpiece.
 2. The system of claim 1,further comprising: a coaxial voltage cable comprising an inner wiredisposed within an outer wire separated by an insulating layer, thecoaxial cable supplying the controlled voltage from the welding machineto the gasless torch.
 3. The system of claim 1, further comprising: avoltage sensor included on the gasless torch for sensing an arc voltageat the tubular workpiece; wherein the welding machine is configured foradjusting the controlled voltage supplied by the welding machine to thetorch in response to the arc voltage sensed by the voltage sensor. 4.The system of claim 3, wherein a magnitude of a difference between thecontrolled voltage supplied by the welding machine and the arc voltagesensed by the voltage sensor is less than 1 volt (V).
 5. The system ofclaim 1, further comprising: a user interface in electricalcommunication with the mechanized carrier, for controlling one or bothof motion of the mechanized carrier along the guide track and lateralposition of the gasless torch relative to the weld path in response toreal-time user input during welding of the tubular workpiece.
 6. Thesystem of claim 1, further comprising: an automatic controller inelectrical communication with the mechanized carrier, the automaticcontroller comprising an optical sensor for sensing a position of themechanized carrier and for controlling motion of the mechanized carrieralong the guide track in response to the sensed position.
 7. The systemof claim 1, wherein an enclosure is not provided about the tubularworkpiece when welding the tubular workpiece.
 8. The system of claim 1,further comprising: a skid supporting at least the welding machine andthe boom, the skid being transported to a work site on a transportvehicle.
 9. The system of claim 8, wherein the transport vehiclecomprises: a band of non-metal treads driven by two or more wheels. 10.The system of claim 9, wherein the lifting arm is moveably supported onthe skid to adjust the position of the helper station with respect tothe tubular workpiece at least by moving the lifting arm.
 11. The systemof claim 8 whereas the skid is transportable on a transport vehiclewithout disassembly.
 12. The system of claim 1, further comprising oneor more user controls for a user to operate one or more of the weldingmachine, the wire feeder, and the boom.
 13. The system of claim 1,wherein the tubular workpiece comprises one or more pipeline segments tobe welded end-to-end.
 14. The system of claim 13, wherein the weld pathis along an interface between two adjacent pipeline segments end-to-end.15. The system of claim 1, wherein the weld path is along a portion of apipeline to be repaired.
 16. The system of claim 1, further comprising:a collapsible cover coupled to the boom, the collapsible cover moveablebetween an expanded position that covers an area overhead of one or moreof the helper station, the mechanized carrier, and a portion of thetubular workpiece including the weld path, and a collapsed position. 17.The system of claim 1, further comprising: an attachment mechanism forinterchangeably supporting the gas shielded/gasless torch or one or moreother tools, the one or more other tools selected from the groupconsisting of a paint sprayer and a sand blaster.
 18. The system ofclaim 1, wherein the power supply comprises a chassis having amaintenance panel and an electrical outlet panel on a same side of thechassis.
 19. The system of claim 1, further comprising: a wirelessconnection configured for data gathering and/or transmission from theskid and/or helper station to a remote location.
 20. A portable helperstation for welding a workpiece, the helper station comprising: a framepositionable to orient the helper station with respect to the workpiece,the frame transportable to a welding site and removably securable to alifting arm; a wire feeder carried on the frame, the wire feederconfigured for feeding a consumable welding wire to a gas shielded orgasless torch in electrical communication with a welding machine togenerate an electrical arc between the consumable welding wire and theworkpiece; and a user interface electrically connected and physicallymountable on the frame, including at least a first controller configuredto operate the wire feeder.
 21. The portable helper station of claim 20,further comprising: a guide track removably positionable about theworkpiece; and a mechanized carrier moveably secured to the guide trackand moveable along the guide track while holding the gas shielded orgasless torch adjacent to the workpiece, the mechanized carrier inelectrical communication with the user interface; and wherein the guidetrack and mechanized carrier are transportable to the welding site. 22.The portable helper station of claim 21, wherein the workpiece is atubular workpiece and the guide track is oriented along a circumferenceof the tubular workpiece to guide the mechanized carrier along thecircumference of the tubular workpiece.
 23. The portable helper stationof claim 21, wherein the user interface is further for remote control ofa welding process including one or both of motion of the mechanizedcarrier along the guide track and lateral position of the gas shieldedor gasless torch relative to the weld path in response to real-time userinput during welding of the workpiece.
 24. The portable helper stationof claim 20, wherein the lifting arm is controllable by the userinterface to raise, lower, and/or rotate the lifting arm.
 25. Theportable helper station of claim 20, further comprising: a coaxialvoltage cable comprising an inner wire disposed within an outer wireseparated by an insulating layer, the coaxial cable supplying thecontrolled voltage from the welding machine to the gas shielded orgasless torch.
 26. The portable helper station of claim 20, furthercomprising: a voltage sensor included on the gas shielded or gaslesstorch for sensing an arc voltage at the workpiece; and wherein thewelding machine is configured for adjusting the controlled voltagesupplied by the welding machine to the torch in response to the arcvoltage sensed by the voltage sensor.
 27. The portable helper station ofclaim 20, further comprising: an attachment mechanism forinterchangeably supporting the gas shielded or gasless torch or one ormore other tools, the one or more other tools selected from the groupmay consist of a paint sprayer, sand blaster, heating apparatus or anyother apparatus
 28. The portable helper station of claim 20, furthercomprising: a collapsible cover securable to the lifting arm, thecollapsible cover moveable between an expanded position and a collapsedposition, wherein the collapsible cover covers an area overhead of atleast the helper station in the expanded position.